Well, I have this relationship:

question
PK ano
PK semestre
PK codigo

reply
PK ano
PK semestre
PK cod_question
PK cod_reply

FK
question.ano --> reply.ano
question.semestre --> reply.semestre
question.cod_question --> reply.codigo
FK
type_reply.ano --> reply.ano
type_reply.semestre --> reply.semestre
type_reply.codigo --> reply.cod_reply

type_reply
PK ano
PK semestre
PK codigo

Xml's:

Question:

<hibernate-mapping>
<class
name="custom.entities.dbweb.QuestionarioPergunta"
table="question"
>
<composite-id name="id" class="custom.entities.dbweb.QuestionarioPerguntaId">
<key-property name="ano"
column="ano"/>
<key-property name="semestre"
column="semestre"/>
<key-property name="pergunta"
column="codigo"/>
</composite-id>

!!! Problem!!!
<set name="respostas">
<key>
<column name="ano"/>
<column name="semestre"/>
<column name="codigo"/>
</key>
<many-to-many class="custom.entities.dbweb.QuestionarioResposta">
<column name="cod_reply"/>
</many-to-many>
</set>
</class>
</hibernate-mapping>

Reply:

<hibernate-mapping
>
<class
name="custom.entities.dbweb.QuestionarioResposta"
table="reply"
>
<composite-id name="id" class="custom.entities.dbweb.QuestionarioRespostaId">
<key-property name="ano"
column="ano"/>
<key-property name="semestre"
column="semestre"/>
<key-property name="question"
column="cod_question"/>
<key-property name="reply"
column="cod_reply"/>
</composite-id>

<many-to-one name="question" class="custom.entities.dbweb.QuestionarioPergunta"
update="false"
insert="false"
>
<column name="ano"/>
<column name="semestre"/>
<column name="cod_question"/>
</many-to-one>

<many-to-one name="reply" class="custom.entities.dbweb.TipoResposta"
update="false"
insert="false"
>
<column name="ano"/>
<column name="semestre"/>
<column name="cod_reply"/>
</many-to-one>

</class>

</hibernate-mapping>

type_reply:

<hibernate-mapping
>
<class
name="custom.entities.dbweb.TipoResposta"
table="type_reply"
>
<composite-id name="id" class="custom.entities.dbweb.TipoRespostaId">
<key-property name="ano"
column="ano"/>
<key-property name="semestre"
column="semestre"/>
<key-property name="resposta"
column="codigo"/>
</composite-id>

</hibernate-mapping>

So????

org.hibernate.MappingException: Foreign key (FK8B2DBD72A6E2ED8E:respostas [cod_reply])) must have same number of columns as the referenced primary key (reply [ano,semestre,cod_question,cod_reply])